Dunkirk may be Christopher Nolan’s shortest film since his 1998 debut Following — clocking in at a brisk 107 minutes — but that hardly means it’s his slightest. An epic about the real-life evacuation of the beaches of Dunkirk, France, by Allied forces during WWII, Nolan’s latest is aiming to deliver a grand wartime saga of heroism and sacrifice when it lands in theaters next Friday. And as he’s now written in an extensive article for The Telegraphin the U.K., one of his many goals with the project was to make audiences feel like they were really in the thick of the action — and that’s just the way he shot it:

“My pitch to Warner Bros was: we’re going to put the audience into the cockpit of a Spitfire and have them dogfight the Messerschmitts. We’re going to put them on the beach, feeling the sand getting everywhere, confronting the waves. We’re going to put them on small civilian boats bouncing around on the waves on this huge journey heading into a terrifying war zone. It’s virtual reality without the headset.”

To create such an atmosphere, Nolan avoided CGI whenever possible, shot on the water with handheld cameras, and worked with real period-era planes, all in order to enhance the authenticity. And in order to craft a real sense of urgency, he writes that he got in close proximity to the chaotic action:

“My cinematographer Hoyte van Hoytema and I put wetsuits or drysuits on; he had housings made for the cameras so they could go out in the waves: when it came to open-water work, the camera could actually float half in, half out of the water.

“We were in there, swimming with the actors. The fact that we were able to be out there with them, experiencing what they were dealing with, defined the spirit of those scenes. Being in it together and not sitting in a tent looking at video is vital for this kind of film, if you’re going to keep up morale and if you’re going to put the audience right there, in the action.”

By splitting his narrative between three focal points — military operations on land, sea, and air — Nolan writes he sought to provide not only a more comprehensive view of the massive campaign, but also to suggest that these are merely a few of the many stories that actually took place at Dunkirk:

“And that is the approach we have taken in the film: to try to suggest to the audience that they’re seeing aspects of the evacuation, but that there are myriad other stories. With so many people involved — 400,000 people on a beach, give or take — you discover a lot of radically different experiences. You find order, but you also find chaos. You find nobility, but also cowardice.”

Meanwhile, in a new video interview, Nolan discussed his own support for 4K home-video transfers, which he says deliver a resolution much closer to that of celluloid. As he notes, he’s now involved in remastering his own movies in that format for a future release, meaning brand-new editions of the Dark Knight trilogy might be on the horizon.

To read all of Nolan’s piece about Dunkirk, head over to The Telegraph. The film opens in the U.S. on July 21.